The project is in a healthy, maintained state
Fork of the ActiveRecord JDBC adapter with support for SQL Server and Azure SQL, for more information and help look at the README file in the github repository. AR-JDBC is a database adapter for Rails' ActiveRecord component designed to be used with JRuby built upon Java's JDBC API for database access. Provides (ActiveRecord) built-in adapters: MySQL, PostgreSQL, SQLite3, and SQLServer.
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ActiveRecord JDBC Alternative Adapter

This adapter is a fork of the ActiveRecord JDBC Adapter with basic support for SQL Server/Azure SQL. This adapter may work with other databases supported by the original adapter such as MySQL but it is advised to use the original adapter

This adapter only works with JRuby and it is advised to install the latest stable of this adapter and Rails

Gem Version Rails Version min JRuby
50.7.0 5.0.7 9.1.x
51.7.0 5.1.7 9.1.x
52.6.0 5.2.4 9.1.x
60.1.0 6.0.3 9.2.9
61.0.0 6.1.3 9.2.16

This adapter passes most of the Rails tests (ActiveRecord tests) with the exception of some test that are not compatible with the SQL Server. To run the test use the following fork Rails, and the instructions in file The fork has some schema tweaks to make it compatible with SQL Server.

How to use it:

Add the following to your Gemfile:

platforms :jruby do
  # Use jdbc as the database for Active Record
  gem 'activerecord-jdbc-alt-adapter', '~> 61.0.0'
  gem 'jdbc-mssql', '~> 0.9.0'

Or look at the sample rails and see how is set up:

Breaking changes

  • This adapter let SQL Server be SQL Server, it does not make SQL Server to be more like MySQL or PostgreSQL, The query will just fails if SQL Server does not support that SQL dialect.
  • This adapter uses the datetime2 sql data type as the Rails logical datetime data type.
  • This adapter needs the mssql jdbc driver version 7.0.0 onwards to work properly, therefore you can use the gem jdbc-mssql version 0.6.0 onwards or the actual driver jar file version 7.0.0.


If you have the old sql server datetime data type for created_at and updated_at, you don't need to upgrade straightaway to datetime2, the old data type (datetime_basic) will still work for simple updates, just make you add to the time zone aware list. If you have complex datetime queries it is advised to upgrade to datetime2

# time zone aware configuration.
config.active_record.time_zone_aware_types = [:datetime, :datetime_basic]

In order to avoid deadlocks it is advised to use SET READ_COMMITTED_SNAPSHOT ON Make sure to run ALTER DATABASE your_db SET READ_COMMITTED_SNAPSHOT ON against your database.

If you prefer to use the READ_UNCOMMITED transaction isolation level as your default isolation level, add the transaction_isolation: 'read_uncommitted' in your database config.

If you have slow queries on your background jobs and locking queries you can change the default lock_timeout config, add the lock_timeout: 10000 in your database config.

database config example (database.yml):

# SQL Server (2012 or higher)

default: &default
  adapter: sqlserver
  encoding: utf8

  <<: *default
  host: localhost
  database: sam_development
  username: SA
  password: password
  transaction_isolation: read_uncommitted
  lock_timeout: 10000

  <<: *default
  host: localhost
  database: sam_test
  username: SA
  password: password

  <<: *default
  host: localhost
  database: sam_production

ActiveRecord JDBC Adapter

Gem Version

ActiveRecord-JDBC-Adapter (AR-JDBC) is the main database adapter for Rails' ActiveRecord component that can be used with JRuby. ActiveRecord-JDBC-Adapter provides full or nearly full support for: MySQL, PostgreSQL, SQLite3 and MSSQL* (SQLServer).

Unless we get more contributions we will not be supporting more adapters. Note that the amount of work needed to get another adapter is not huge but the amount of testing required to make sure that adapter continues to work is not something we can do with the resources we currently have.

Versions are targeted at certain versions of Rails and live on their own branches.

Gem Version Rails Version Branch min JRuby min Java
50.x 5.0.x 50-stable 9.1.x 7
51.x 5.1.x 51-stable 9.1.x 7
52.x 5.2.x 52-stable 9.1.x 7
60.x 6.0.x 60-stable 9.2.7 8
61.x 6.1.x master 9.2.7 8

Note that JRuby 9.1.x is end-of-life. We recommend Java 8 at a minimum for all versions.

Using ActiveRecord JDBC

Inside Rails

To use AR-JDBC with JRuby on Rails:

  1. Choose the adapter you wish to gem install. The following pre-packaged adapters are available:
  • MySQL (activerecord-jdbcmysql-adapter)
  • PostgreSQL (activerecord-jdbcpostgresql-adapter)
  • SQLite3 (activerecord-jdbcsqlite3-adapter)
  • MSSQL (activerecord-jdbcsqlserver-adapter)
  1. If you're generating a new Rails application, use the following command:

    jruby -S rails new sweetapp

  2. Configure your database.yml in the normal Rails style:

  adapter: mysql2 # or mysql
  database: blog_development
  username: blog
  password: 1234

For JNDI data sources, you may simply specify the JNDI location as follows, it's recommended to use the same adapter: setting as one would configure when using "bare" (JDBC) connections e.g. :

  adapter: postgresql
  jndi: jdbc/PostgreDS

NOTE: any other settings such as database:, username:, properties: make no difference since everything is already configured on the JNDI DataSource end.

JDBC driver specific properties might be set if you use an URL to specify the DB or preferably using the properties: syntax:

  adapter: mysql
  username: blog
  password: blog
  url: "jdbc:mysql://localhost:3306/blog?profileSQL=true"
  properties: # specific to com.mysql.jdbc.Driver
    socketTimeout:  60000
    connectTimeout: 60000

MySQL specific notes

Depending on the MySQL server configuration, it might be required to set additional connection properties for date/time support to work correctly. If you encounter problems, try adding this to your database configuration:

    serverTimezone: <%= java.util.TimeZone.getDefault.getID %>

The correct timezone depends on the system setup, but the one shown is a good place to start and is actually the correct setting for many systems.

Standalone with ActiveRecord

Once the setup is made (see below) you can establish a JDBC connection like this (e.g. for activerecord-jdbcderby-adapter):

  adapter: 'sqlite3',
  database: 'db/my-database'

Using Bundler

Proceed as with Rails; specify ActiveRecord in your Bundle along with the chosen JDBC adapter(s), this time sample Gemfile for MySQL:

gem 'activerecord', '~> 6.0.3'
gem 'activerecord-jdbcmysql-adapter', '~> 60.2', :platform => :jruby

When you require 'bundler/setup' everything will be set up for you as expected.

Without Bundler

Install the needed gems with JRuby, for example:

gem install activerecord -v "~> 6.0.3"
gem install activerecord-jdbc-adapter -v "~> 60.2" --ignore-dependencies

If you wish to use the adapter for a specific database, you can install it directly and the (jdbc-) driver gem (dependency) will be installed as well:

jruby -S gem install activerecord-jdbcmysql-adapter -v "~> 60.2"

Your program should include:

require 'active_record'
require 'activerecord-jdbc-adapter' if defined? JRUBY_VERSION


The source for activerecord-jdbc-adapter is available using git:

git clone git://

Please note that the project manages multiple gems from a single repository, if you're using Bundler >= 1.2 it should be able to locate all gemspecs from the git repository. Sample Gemfile for running with (MySQL) master:

gem 'activerecord-jdbc-adapter', :github => 'jruby/activerecord-jdbc-adapter'
gem 'activerecord-jdbcmysql-adapter', :github => 'jruby/activerecord-jdbc-adapter'

Getting Involved

Please read our CONTRIBUTING & RUNNING_TESTS guides for starters. You can always help us by maintaining AR-JDBC's wiki.


Please report bugs at our issue tracker. If you're not sure if something's a bug, feel free to pre-report it on the mailing lists or ask on the #JRuby IRC channel on (try web-chat).


This project was originally written by Nick Sieger and Ola Bini with lots of help from the JRuby community. Polished 3.x compatibility and 4.x support (for AR-JDBC >= 1.3.0) was managed by Karol Bucek among others. Support for Rails 6.0 and 6.1 was contributed by shellyBits GmbH


ActiveRecord-JDBC-Adapter is open-source released under the BSD/MIT license. See LICENSE.txt included with the distribution for details.

Open-source driver gems within AR-JDBC's sources are licensed under the same license the database's drivers are licensed. See each driver gem's LICENSE.txt.